Cooking terms can be stupidly confusing sometimes and if you have a recipe that calls for a béchamel or roux, you might wonder what the difference is.
A roux is a mixture of (usually) equal quantities of flour and butter that’s used as a thickening agent in sauces. A béchamel is a sauce made using a roux with the addition of (usually) milk. This gives you a basic white sauce that can be used as the basis for all sorts of other creamy sauces, like cheese, parsley, mushroom, onion etc.
Although a roux is usually a 50-50 mix of flour and butter, adding a little extra butter makes the sauce easier to blend and less likely to go lumpy. Infusing the milk with a few flavourings first helps make the sauce taste better but you can skip this step if you’re in a hurry.
NB: I’ve given a recipe for a basic béchamel using milk but you may find some recipes call for a mixture of milk and cooking liquid or stock.
300 ml milk
1 bay leaf
6 whole black peppercorns
25g plain flour
Salt and pepper
Put the milk in a saucepan with the peeled onion, peppercorns and bay leaf and bring to the boil. Immediately remove from the heat and leave the flavours to infuse for an hour or so. Strain the milk and discard the flavourings. Before you start making the sauce, gently re-heat the infused milk, it’ll make cooking the béchamel much speedier.
In a heavy-based pan, melt the butter over a gentle heat and blend in the flour to form a stiff paste (the roux). Cook gently for about a minute until it lightens in colour and takes on a sandy texture. This will help cook out the floury taste.
Gradually pour in the warmed milk, whisking well all the time and making sure you incorporate all the bits from the edges of the pan. When all the milk has been added, bring to the boil, stirring all the time. Lower the heat and simmer gently, stirring, until the mixture is thick and glossy. Add salt and pepper to taste.
If you want to make this in advance, allow it to cool a little, stir well then put cling film over the surface of the sauce to stop a skin forming.
For cheese sauce, stir about 50g of Parmesan and 50g of Cheddar (or for a classic sauce use Gruyère) into the cooked sauce and cook over a gentle heat until the cheese has blended in. A small grating of nutmeg is a good addition.
For parsley sauce, add 2 tbsp of finely chopped parsley to the cooked sauce.
For onion sauce (sauce soubise), peel two medium onions, put them in a pan, cover with water and boil until soft. Drain well, purée in a food processor and add to the cooked sauce with a small splash of cream.
For mushroom sauce, fry a big handful of cleaned and finely chopped mushrooms in a little butter and add them to the cooked sauce with a squeeze of lemon juice.